THIS invention relates to a pipe coupling and, in particular, to a Victaulic-type coupling.
Victaulic couplings generally comprise a pair of half shells, together forming a sleeve which can be placed around adjacent shouldered or grooved ends of a pair of pipes which have been located in co-axial end to end relationship for joining. The half shells are formed with ridges which are adapted to fit into or around the formations on the pipe to secure the pipe ends together in a strong mechanical joint. A rubber sealing ring is located within a channel formed within the sleeve defined by the half shells, to provide a fluid tight joint.
In prior art Victaulic couplings, the half shells are provided with securement ends, constituted by radially projecting flanges which are formed with bolt holes through which bolts can be passed for fastening by means of nuts.
The problem with couplings of this type is that they frequently require more than one person to assemble, particularly in confined spaces, since, in essence, more than one pair of hands is needed to hold the two half shells together and to insert the bolts into the bolt holes.
Pipe couplings are known in which the half shells are interconnected or releasably interconnectable. U.S. Pat. No. 4,391,458--Blakeley Engineering Limited--describes a pipe coupling of the first kind in which the two half shells are hinged together at one pair of engagement flanges and intended for securement by means of a bolt and nut arrangement, at the opposed pair of engagement flanges.
UK Patent Application No. 2,161,882--Stanton and Staveley Limited--describes a variation on this format. In this patent, the half shells are hinged together on formations which, in essence, constitute a separable hinge, so that the half shells are separably interconnected. The interconnectability of the half shells overcomes the problem mentioned above, namely that of requiring two people to assemble the coupling on a pair of pipe ends, since the half shells, once interconnected on the hinge formation, are, at least, retained in position on the pipe ends. This means that a single person can manoeuvre the coupling and the pipe ends with one hand, while securing the half shells together with the bolt and nut, using the other hand.
However, this coupling comprises non-identical half shells, which leads to increased manufacturing and inventory costs.
An example of the use of identical half shells is described in U.S. Pat. No. 4,408,788--Grinell Fire Protection Systems Company, Inc.--in which the radially extending securement flanges are tapered to allow the half shells to swing open after the attachment, to one of the securement flanges, of the bolt and nut fastening.
This does not completely overcome the problems of the prior art, since the half shells are not readily disengagable in the open the position.